Dynamic bushing for medical device tubing

ABSTRACT

A dynamic bushing and/or gripper mechanism comprises an apparatus for retaining a tubular member in a position during processing so that the tube does not move transverse to the longitudinal axis of the bushing, but wherein the tube may be rotated within the confines of the bushing and/or in the case of the gripper mechanism the tube may be moved longitudinally within the confines of the gripper.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable

BACKGROUND OF THE INVENTION

A stent is a radially expandable endoprosthesis which is adapted to beimplanted in a body lumen. Stents are typically used in the treatment ofatherosclerotic stenosis in blood vessels and the like to reinforce bodyvessels and to prevent restenosis following angioplasty in the vascularsystem. They have also been implanted in urinary tracts, bile ducts andother bodily lumen. They may be self-expanding or expanded by aninternal radial force, such as when mounted on a balloon.

Delivery and implantation of a stent is accomplished by disposing thestent about a distal portion of the catheter, percutaneously insertingthe distal portion of the catheter in a bodily vessel, advancing thecatheter in the bodily lumen to a desired location, expanding the stentand removing the catheter from the lumen. In the case of a balloonexpandable stent, the stent is mounted about a balloon disposed on thecatheter and expanded by inflating the balloon. The balloon may then bedeflated and the catheter withdrawn. In the case of a self-expandingstent, the stent may be held in place on the catheter via a retractablesheath. When the stent is in a desired bodily location, the sheath maybe withdrawn allowing the stent to self-expand.

In the past, stents have been generally tubular but have been composedof many configurations and have been made of many materials, includingmetals and plastic. Ordinary metals such as stainless steel have beenused as have shape memory metals such as Nitinol and the like. Stentshave also been made of bio-absorbable plastic materials. Stents havebeen formed from wire, tube stock, etc. Stents have also been made fromsheets of material which are rolled.

A number of techniques have been suggested for the fabrication of stentsfrom sheets and tubes. One such technique involves laser cutting apattern into a sheet of material and rolling the sheet into a tube ordirectly laser cutting the desired pattern into a tube. Other techniquesinvolve cutting a desired pattern into a sheet or a tube via chemicaletching or electrical discharge machining.

Laser cutting of stents has been described in a number of publicationsincluding U.S. Pat. No. 5,780,807 to Saunders, U.S. Pat. No. 5,922,005to Richter and U.S. Pat. No. 5,906,759 to Richter. Other referenceswherein laser cutting of stents is described include: U.S. Pat. No.5,514,154, U.S. Pat. No. 5,759,192, U.S. Pat. No. 6,131,266 and U.S.Pat. No. 6,197,048.

Past laser cutting systems typically mount the tube to be cut from aspindle shaft or other rotary assembly wherein the laser is mountedperpendicular to the longitudinal axis of the tube. To maintain theposition of the tube relative to the laser during the cutting process,the tube is typically guided through a rigid or fixed bushing whichconstrains the tube from moving transverse to the longitudinal axis ofthe tube. However, if the tube has any outer diameter variations thetube will be capable of slight movement within the bushing andpotentially move in and out of focus of the laser resulting in impropercutting of the tube. Current bushing designs are very operator dependentand do not allow for any tubing variability and are thus difficult andtime consuming to use and maintain.

In light of the above a need exists to provide a more dynamic bushingwith is capable of maintaining the position of the tube, while beingable to accommodate a wide variety of tube diameters and surfacefeatures without requiring extensive modification or manually sizing ofthe bushing for every tube used therewith.

All US patents and applications and all other published documentsmentioned anywhere in this application are incorporated herein byreference in their entirety.

Without limiting the scope of the invention a brief summary of some ofthe claimed embodiments of the invention is set forth below. Additionaldetails of the summarized embodiments of the invention and/or additionalembodiments of the invention may be found in the Detailed Description ofthe Invention below.

A brief abstract of the technical disclosure in the specification isprovided as well only for the purposes of complying with 37 C.F.R. 1.72.The abstract is not intended to be used for interpreting the scope ofthe claims.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a variety of embodiments. In atleast one embodiment the invention is directed to a system for cutting,etching and/or otherwise processing a hollow metal tube formanufacturing a stent. In some embodiments the tube is engaged to arotary assembly for rotating the tube relative to a laser or otherprocessing tool. In order to prevent the tube from moving transverse tothe longitudinal axis of the tube the tube is passed through a dynamicbushing. A dynamic bushing may be embodied in a variety of forms. Forexample:

In at least one embodiment a dynamic bushing comprises a top dead centerguide and at least two bottom guides, wherein the at least two bottomguides are adjustably positioned relative to the to dead center guide todefine a variable tube retention area. In some embodiments the bottomguides are positioned apart on a piston or other moveable member. Apressure regulator, servo proportional regulator, a biasing assembly orother device may be used to push the piston and thus the bottom guidestoward the top dead center guide. In this manner a wide range of tubediameters may be held within the tube retention area without creating anundesirable amount of friction between the external surface of the tubeand the various guides. In at least one embodiment one or more of theguides comprise independently adjustable rolling balls whichindividually contact the tube at single point. In some embodiments oneor more of the guides comprise adjustable leaf springs.

In at least one embodiment a dynamic bushing comprises a grove in whicha tube to be processed is positioned. In some embodiments the groove issubstantially V-shaped so as to contact the tube along only two lines orregions of contact. An adjustable arm or other member applies anadjustable force to the tube from the exposed ‘top’ of the groove, toprovide a third line or region of contact. Where the bushing and rotaryassembly are configured to process the tube in a horizontalconfiguration the amount of force applied by the arm to the tube may bevaried depending on the weight of the arm or a ballast attached thereto.In a vertical stent processing application such as is described inco-pending U.S. patent application Ser. No. 10/190,975, filed Jul. 8,2002, the arm may retain the tube within the groove by utilizing acompression spring, pneumatic or hydraulic cylinder, or other device tovary the force directed to the tube by the arm. In some embodiments thedimensions of the groove may be varied. In some embodiments the grooveand/or arm defines one or more fluid holes through which a coolant orother fluid may be passed to create a positive pressure to preventdebris from entering the tooling.

In at least one embodiment the dynamic bushing comprises a hydraulicchamber into which at least a portion of the tube is guided. Fluid isinjected into the chamber from one or more injection ports. A glandplate is positioned adjacent to the ends of the chamber in order toregulate pressure and limit release of fluid from the chamber. Whenfluid is injected into the chamber when a, tube is positioned therein,the chamber acts as a hydraulic bearing as long as the fluid supplied tothe chamber exceeds the fluid lost through the gland plates. In someembodiments one or both gland plates define a labyrinth to createpressure decreasing zones to minimize loss of fluid from the chamber. Inuse the chamber provides a uniform pressure equally to all surfaces ofthe tube thus providing a highly accurate centering function.

In at least one embodiment of the invention a processing system maycomprise a gripper mechanism. In some embodiments the gripper mechanismcomprises a pneumatically actuated gripper having two jaws that aremoveable between a release position and a gripping position. In someembodiments the gripper is mounted on a low friction pivot forself-alignment of the gripper relative to the tubing to be processed. Insome embodiments a processing system comprises a dynamic bushing and agripper mechanism.

These and other embodiments which characterize the invention are pointedout with particularity in the claims annexed hereto and forming a parthereof. However, for a better understanding of the invention, itsadvantages and objectives obtained by its use, reference should be madeto the drawings which form a further part hereof and the accompanyingdescriptive matter, in which there is illustrated and describedembodiments of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

A detailed description of the invention is hereafter described withspecific reference being made to the drawings.

FIG. 1 is a side view of an embodiment of the invention.

FIG. 2 is a close-up side view of the retention area of the embodimentshown in FIG. 1 wherein a tube is engaged therein.

FIG. 3 is a close-up side view of the retention area of the embodimentshown in FIG. 1 wherein the tube is not fully engaged therein.

FIG. 4 is a cross-sectional view of an example of a guide mechanismsuitable for use in the embodiment shown in FIG. 1.

FIG. 5 is a perspective view of an embodiment of the invention.

FIG. 6 is a cross-sectional side view of the embodiment shown in FIG. 5

FIG. 7 is a perspective view of an embodiment of the invention similarto that shown in FIG. 5, wherein the top plate or arm in the openposition and the ballast is replaced with a compression spring assembly.

FIG. 8 is an exploded view of the embodiment shown in FIG. 7.

FIG. 9 is a perspective view of an embodiment of the invention.

FIG. 10 is a longitudinal cross-sectional view of an embodiment of theinvention.

FIG. 11 is a partial perspective view of an embodiment of the inventioncomprising a tubular cutting system having a gripping mechanism anddynamic bushing.

FIG. 12 is a partial perspective view of the embodiment shown in FIG. 11wherein the gripping mechanism is illustrated in detail.

DETAILED DESCRIPTION OF THE INVENTION

While this invention may be embodied in many different forms, there aredescribed in detail herein specific preferred embodiments of theinvention. This description is an exemplification of the principles ofthe invention and is not intended to limit the invention to theparticular embodiments illustrated.

For the purposes of this disclosure, like reference numerals in thefigures shall refer to like features unless otherwise indicated.

As indicated above the present invention is directed to a variety ofembodiments. In at least one embodiment, shown in FIG. 1, the inventionis directed to a dynamic bushing assembly (assembly), indicatedgenerally at 10, for constraining the tube 12 when an end of the tube 12is engaged to a tubular member cutting system or rotary assembly 200,such as the example shown in FIG. 11, for use in processing the tubeinto a stent or other device.

In the embodiment shown in FIG. 1, a portion of the tube 12 is passedthrough and positioned within a tube retention area 14. The retentionarea 14 is defined by at least two bottom guides 16 and 18 and at leastone top or center guide 20. One or more of the guides 16, 18 and 20 areadjustable in position relative to the others to allow the effectivediameter of the retention area 14 to be expanded or contracted asdesired depending on the diameter of the outer surface 15 and/or otherexternal surface characteristics of the tube 12.

In at least one embodiment the top guide 20 is statically mounted to acrown 22. Crown 22 may be any type of structure or member suitable formaintaining the top guide 20 in a stable position during processing ofthe tube 12. In at least one embodiment, such as in the example shown,the crown 22 is a substantially U-shaped member with the top guideengaged to the crown at the internal apex 24 of the crown 22.

In order to provide a retention area 14 which is of an appropriate shapeto receive a tube 12 the bottom members are positioned on asubstantially concave platform 26. Platform 26 defines a surface of apiston 28 which may be adjustably positioned relative to the crown 22,thereby providing a mechanism for moving the guides 16 and 18 relativeto the top guide 20. Thus by moving the piston 28 and the associatedguides 16 and 18 away from the top guide 20 the retention area may beenlarged, and by moving the piston 28 toward the top guide 20 the sizeof the retention area 14 is reduced.

To provide the assembly 10 with improved stability, the piston 28 ispositioned within a piston housing 30 which prevents the piston 28 frommoving lateral to the tube 12 regardless of the position of the piston28 relative to the top guide 20. The housing 30 is mounted to and atleast partially contained within a cradle 32 which may be moveably orfixedly engaged to a floor or other surface upon which the assembly 10rests. In some embodiments the cradle 32 is engaged to a base 34 havingan elevator mechanism 36 which allows the cradle 32 and componentssupported thereby to be vertically repositioned as desired.

As is shown in FIG. 2, a tube 12 is retained within the retention area14, when the piston 28 is moved adjacent to the top guide 20 so that theouter surface 15 of the tube 12 is in contact with all three guides 16,18 and 20.

In some embodiments at least guides 16 and 18 may be independentlymoveably adjustable relative to each other along the platform 26.

In the embodiment shown in FIGS. 2 and 3 the guides 16, 18 and 20 aredefined by a guide housing 50 which contains a biasing mechanism 52. Thebiasing mechanism 52 biases a bearing or roller ball 54 in an outwarddirection away from the housing 50. By moving the guides 16, 18 towardthe top guide 20 the roller balls 54 of each guide 16, 18 and 20 contactthe outer surface 15 of the tube 12 at a single point respectively. Theroller balls 54 of each guide are freely rotatable within the housings50, as a result, when the roller balls 54 contact the tube 12, the tube12 is able to be rotated about a longitudinal axis 60, but remainsrestrained from moving transverse to the longitudinal axis 60 aboutwhich the tube is disposed such as is shown in FIG. 2.

In order to prevent excess wear on the roller balls 54, in someembodiments the balls 54 are at least partially constructed from orcoated with a ceramic, crucible powder metal, tungsten carbide, and/orother hard wear resistant material.

The biasing mechanism 52 within each housing 50 may be any type ofmechanism which expresses a K-factor or biasing force, such as forexample a spring, a pressurized fluid column, hydraulic mechanism, etc.The K-factor or amount of biasing force of each guide 16, 18 and 20 maybe independently adjusted as desired. In at least one embodiment theK-factor expressed by the top guide 20 is greater than that of thebottom guides 16 and 18.

In an alternative embodiment of the guides shown in FIGS. 2 and 3, oneor more of the guides 16, 18 and 20 may comprise a leaf spring 62 suchas is shown in FIG. 4. In the case of the bottom guides 16 and 18, afirst end 64 of each leaf spring 62 is adjustably engaged to theplatform 26 of piston 28. The second end 66 of the leaf spring 62extends outwardly away from the first end 64 to define an adjustablebiasing angle 68. The second end 66 of each leaf spring 62 is designedto tangentially contact the tube 12 when the piston is moved intoposition to secure the tube 12 within the retention area 14. In the caseof the top guide 20 the first end 64 of the leaf spring is adjustablyengaged to the crown 22.

An alternative embodiment of the invention is shown in FIGS. 5-8,wherein a the assembly 10 is comprised of a base block 80 whichpartially defines a substantially V-shaped tube retention area 14 withinwhich tube 12 is retained during a stent cutting process. Retention area14, is defined on two sides by V-groove 70 portion of the base block 80.As is best shown in FIG. 6, the V-groove 70 comprises two sides 72 and74 which form an angle 76 greater than 0 degrees but less than 180degrees. In at least one embodiment the angle 76 is between about 45degrees and about 135 degrees.

In some embodiments the angle 76 and thus the distance between sides 72and 74 may be varied to accommodate a wide variety of tube outerdiameters. However, even in an embodiment where the angle 76 is fixed awide range of tube diameters may be accommodated within the V-groove 70.A tube 12 is retained within the V-groove 70 by engaging each side 72and 74 of the groove at a tangential point or line of contact 77 and 79which is substantially parallel to the longitudinal axis 60 about whichthe tube 12 is mounted. Depending on the outer diameter of the tube 12the position of the lines of contact 77 and 79 relative to the sides 72and 74 will vary. Only if the tube 12 has an outer diameter greater thanthe widest distance between sides 72 and 74 would it be necessary toenlarge the angle 76 to increase the distance between sides 72 and 74.

To prevent wear and minimize friction, the sides 72 and 74 are at leastpartially constructed from a material having a hardness of at least 64as measured on the Rockwell-C hardness scale. In at least one embodimentthe V-groove 70 is a carbide insert within the base block 80.

The sides 72 and 74 may be wire burned, polished and/or coated with amaterial such as titanium nitrate or other hardening agent(s). Ahardening agent may be applied to the sides 72 and 74 by vapordeposition or other desired method. In some embodiments sides 72 and 74are coated with a lubricant.

As is shown in FIGS. 6 and 8, in some embodiments the sides 72 and 74define one or more coolant ports 82 through which a coolant, indicted byarrows 84 may be injected into the retention area 14. The coolant 84creates a positive pressure within the retention area 14 to prevent slagand other debris from entering the assembly 10. Ports 82 pass throughthe block 80 and are in fluid communication with one or more fittings86. Fittings 86 are in turn in fluid communication with a fluid source(not shown). Fluid or coolant 84 may be injected into, as well asremoved, from the V-groove 70 by the one or more fittings 86.

In order to secure the tube 12 within the V-groove 70 a top plate or arm90 is pivotally mounted to the base block 80 at a pivot hinge 99. Asillustrated in FIG. 8, pivot hinge 99 may be a nut and bolt assembly, adowel, or any other retaining mechanism which provides the arm 90 theability to be pivotally engaged to the block 80. The arm 90 is moveablebetween an open position wherein the V-groove is open or uncovered suchas is shown in FIG. 7, and a closed position, shown in FIGS. 5 and 6,wherein the arm 90 overlays the V-groove 70 and tangentially contactsthe tube 12 at a top point or line of contact 81.

As best shown in FIG. 6 by closing the arm 90 over the V-groove 70, atube contained within the retention area 14 will be tangentially engagedalong three lines of contact 77, 79 and 81. The arm 90 may comprise acontact member 94 which is in contact with the tube 12 to form the topline of contact 81. Like the sides 72 and 74 of the V-groove 70, in someembodiments the contact member 94 is a carbide insert or other materialhaving a hardness of at least 64 as measured on the Rockwell-C hardnessscale.

The contact member 94 may be wire burned, polished and/or coated with amaterial such as tin, titanium nitrate, or other hardening agent. Ahardening agent may be applied to the contact member 94 by vapordeposition or other desired method. In some embodiments contact member94 is coated with a lubricant.

In some embodiments such as is shown in FIG. 5, the contact member 94 issubstantially cylindrically shaped. The contact member 94 may be freelyrotatable relative to the arm 90 and the tube 12 to reduce wear on thetube 12 during rotation thereof. Alternatively, the contact member 94may be a flat planar surface, a point or edge or may be any other shapedesired. In some embodiments the contact member 94 may comprise apolyethylene insert.

In the embodiments shown in FIGS. 5 and 6, arm 90 is held in the closedposition over the tube 12 simply as a result of the orientation of theassembly 10 which allows gravity to pull the arm down. If necessary ordesired the arm may comprise a ballast member 96 which providesadditional weight to the arm 90 to ensure the arm remains securely inposition over the V-groove 70. Ballast member 96 may have a weight ofzero to about {fraction (1/2)} of a pound (8 oz., 227 grams). In someembodiments the ballast member 96 weighs about {fraction (1/4)} of apound (4 oz., 113 grams) to about {fraction (3/8)} of a pound (6 oz. 170grams).

In the embodiments shown in FIGS. 7 and 8, a compression spring, aircylinder or other biasing mechanism 98 may be utilized to retain the arm90 in the closed position, rather than a ballast member or gravityalone. A biasing mechanism 98 may be utilized to vary the amount ofdownward force applied to the tube 12 when the arm is in the closedposition.

If desired the assembly 10, such as is shown and described in FIGS. 5and 6 may be inverted, as is shown in FIG. 9, so that the tube 12 tendsto fall away from the sides 72 and 74 of the V-groove 70 unless the arm90 is held in the closed position. In such an inverted embodiment, suchas is shown in FIG. 9 the arm 90 is reconfigured to mount the ballastmember 96 on an opposing end of the arm than in the embodiments of FIGS.5 and 6. Repositioning the ballast member 96 has the affect of allowingthe arm 90 to be biased in an upward direction against the tube 12.

In the various embodiments shown in FIGS. 5-6 and 9 the assembly 10 maybe mounted or otherwise engaged directly to an existing rotary assembly(not shown) using a mounting arm 91. Mounting arm 91 may have any shapeor configuration to allow the assembly 10 to allow the tube 12 to extendfrom the rotary assembly through the dynamic bushing assembly 10 along acommon longitudinal axis 60.

In yet another embodiment of the invention, an example of which is shownin FIG. 10, the assembly 10 may comprise a tooling block 110 whichdefines a retaining area 14 in which a portion of the tube 12 isinserted. The block 110 further defines one or more coolant ports 82which are in fluid communication with the retaining area 14. Coolant orother media 84 is injected into the retaining area 14 through the one ormore ports 82. The media 84 not only acts to cool the tube 12 during thecutting process but also creates a positive pressure within theretaining area 14 to prevent dross, slag or other debris from enteringthe block 110.

Fluid media 84 may be any type of fluid such as including but notlimited to: water, oils, water soluble cutting solutions, etc.

In some embodiments the block 110 defines a first or upstream end 114and a second or downstream end 116. Adjacent to the first end 114 ispositioned an upstream gland plate 120 in fluid communication with theretaining area 14. Adjacent to the second end 116 is positioned adownstream gland plate 124 that is also in fluid communication with theretaining area 14.

In some embodiments each gland plate 120 and 124 defines a labyrinth 122and 126 respectively. Labyrinths 122 and 126 define one or more fluidpressure decreasing zones 130 which act to minimize loss of fluid media84 injected into the retaining area 14.

When a fluid media 84 is injected into the retaining area 14, the media84 forms a hydraulic bearing which retains the tube 12 within theretaining area as long as the media 84 injected into the retaining area,as indicated by arrow 84 a far exceeds the amount of fluid media beinglost through the gland plates 120 and 124. Though the hydraulic bearingcreated by the injection of fluid media 84 retains the tube 12 in theretaining area 14, the tube 12 is free to be rotated by any externalmeans with the fluid media 84 providing a minimum of frictionalinterference.

The hydraulic bearing action of the embodiment shown in FIG. 10 providesa high centering accuracy due to the fact that the tube 12 is supportedby equal pressure on equal surface areas of the tubing. By manipulatingthe fluid pressure, fluid viscosity, and the exposed surface area of theretaining area different process parameters may be attained.

During the cutting of the tube 12 by the rotary assembly 200, such as isdepicted in FIG. 11 a dynamic bushing assembly 10 constrains a distalportion 202 of the tube 12. While a distal portion 202 of the tube 12 isengaged by the dynamic bushing assembly 10, a more proximal portion 204of the tube 12 is engaged by a rear collet 206 which provides furtherstability along the length of the tube 12 during the cutting process.After the cutting of a portion of the tube 12 is complete, the rearcollet 206 is placed in an open configuration to release the tube 12,while the tube 12 remains engaged by the dynamic bushing 10 inaccordance with any of the manners or configurations described herein.Before the tube 12 is released by the rear collet 206, a grippermechanism 210 having at least two engagement members or moveable jaws212 and 214, such as is shown in FIGS. 11 and 12, is actuated from anopen position to a closed position wherein the jaws 212 and 214 aremoved toward one another to grip the tube 12 while the tube is advancedwithin the assembly 200.

In at least one embodiment, jaws 212 and 214 are substantially rigidmembers that may be mounted parallel to one another or may be displacedat any angle desired. Each jaw 212 and 214 is provided with a grippingsurface 216 which is constructed and arranged to engage the tube 12 sothat the lateral movement of the tube is reduced or eliminated but thetube 12 is able to be advanced in a longitudinal direction withoutsignificant resistance. As such, the gripping surface 216 may beconstructed of a variety of materials that may be relatively soft, hard,or a combination and/or composite thereof. In at least one embodimentthe surface 216 is at least partially constructed of one or morerelatively soft pads of natural and/or man-made materials such as wool,cotton, nylon, polyester, cloth, fiber, leather, etc. In someembodiments a relatively hard material may be used in conjunction with arelatively soft material to form the surface 216. For example, in atleast one embodiment the surface 216 comprises a layer of relativelyhard material and a layer of relatively soft material.

In at least one embodiment, the jaws 212 and 214 of the grippermechanism 210 may be pneumatically actuated by a pneumatic source 220.In order to provide the mechanism 210 with a self-centering capabilitythe mechanism 210 includes a counter weight 224 mounted opposite to thejaws 212 and 214. The entire assembly 210 is mounted on and about a lowfriction pivot member 222. The assembly is in substantially balancedgravitational equilibrium about the pivot member 222, which allows thejaws 214 and 214 to self-align on the center of the tube 12 and thusaccommodate a wide range of tube 12 diameters without significant changeover tasks or tooling changes.

The above disclosure is intended to be illustrative and not exhaustive.This description will suggest many variations and alternatives to one ofordinary skill in this art. All these alternatives and variations areintended to be included within the scope of the claims where the term“comprising” means “including, but not limited to”. Those familiar withthe art may recognize other equivalents to the specific embodimentsdescribed herein which equivalents are also intended to be encompassedby the claims.

Further, the particular features presented in the dependent claims canbe combined with each other in other manners within the scope of theinvention such that the invention should be recognized as alsospecifically directed to other embodiments having any other possiblecombination of the features of the dependent claims. For instance, forpurposes of claim publication, any dependent claim which follows shouldbe taken as alternatively written in a multiple dependent form from allprior claims which possess all antecedents referenced in such dependentclaim if such multiple dependent format is an accepted format within thejurisdiction (e.g. each claim depending directly from claim 1 should bealternatively taken as depending from all previous claims). Injurisdictions where multiple dependent claim formats are restricted, thefollowing dependent claims should each be also taken as alternativelywritten in each singly dependent claim format which creates a dependencyfrom a prior antecedent-possessing claim other than the specific claimlisted in such dependent claim below.

This completes the description of the preferred and alternateembodiments of the invention. Those skilled in the art may recognizeother equivalents to the specific embodiment described herein whichequivalents are intended to be encompassed by the claims attachedhereto.

1. A dynamic bushing assembly for preventing a tubular member frommoving transverse to a longitudinal axis defined thereby but permittingthe tube to be rotated about the longitudinal axis, the assemblycomprising: a tube retention area, the tube retention area being definedat least partially defined by a crown member, the crown member definingan apex, the apex having at least one top guide member extendingtherefrom into the tube retention area, the tube retention area beingfurther defined by a substantially concave surface of a piston, thepiston being moveable toward and away from the apex, the substantiallyconcave surface of the piston having at least two bottom guide membersextending therefrom into the tube retention area.
 2. The assembly ofclaim 1 further comprising a piston housing, the piston being moveablyengaged to the piston housing and being moveable therethrough, the crownmember being fixedly engaged to the piston housing.
 3. The assembly ofclaim 2 further comprising a cradle, the cradle being supportivelyengaged to a portion of the piston housing.
 4. The assembly of claim 3further comprising an elevator mechanism, the elevator mechanism beingengaged to at least a portion of the cradle, the elevator mechanismconstructed and arranged to move the cradle in a vertically up and downdirection.
 5. The assembly of claim 1 wherein the at least one top guidecomprises: a guide housing, at a first end of the guide housing theguide housing being engaged to the apex of the crown member, at a secondend of the guide housing a roller ball is frictionally engaged to theguide housing, the roller ball being rotatable relative to the guidehousing, the guide housing containing a biasing mechanism therein, thebiasing mechanism exerting a predetermined biasing force on the rollerball in a direction toward the tube retaining area.
 6. The assembly ofclaim 5 wherein the at least two bottom guides each comprise: a guidehousing, at a first end of the guide housing, the guide housing beingengaged to the substantially concave surface of the piston, at a secondend of the guide housing a roller ball is frictionally engaged to theguide housing, the roller ball being rotatable relative to the guidehousing, the guide housing containing a biasing mechanism therein, thebiasing mechanism, exerting a predetermined biasing force on the rollerball in a direction toward the tube retaining area.
 7. The assembly ofclaim 6 wherein the biasing member of the at least one top guide exertsa predetermined biasing force that is greater than the predeterminedbiasing force exerted by the biasing member of each of the at least twobottom guides.
 8. The assembly of claim 6 wherein the tube retainingarea has a predetermined size, the size of the tube retaining area beingreduced when the piston is moved toward the apex of the crown, the sizeof the tube retaining area being expanded when the piston is moved awayfrom the apex of the crown.
 9. The assembly of claim 8 furthercomprising a tubular member, the tubular member defining an externalsurface, the tubular member being positioned in the tube retaining areaso that the roller ball of the at least one top guide contacts a pointon the external surface of the tubular member and the roller ball ofeach of the at least two bottom guides contact a point on the externalsurface of the tubular member.
 10. The assembly of claim 6 wherein eachroller ball is at least partially constructed from a wear resistantmaterial.
 11. The assembly of claim 10 wherein the wear resistantmaterial is selected from at least one member of the group consistingof: ceramic, crucible powder metal, tungsten carbide and any combinationthereof.
 12. The assembly of claim 6 wherein each biasing mechanism isselected from at least one member of the group consisting of: a biasingmember, a pressurized fluid column, and any combination thereof.
 13. Theassembly of claim 1 wherein the at least one top guide is moveablyengaged to the crown.
 14. The assembly of claim 1 wherein each of the atleast two bottom guides are moveably engaged to the piston.
 15. Theassembly of claim 1 wherein at least one of the at least one top guideand the at least two bottom guides comprise a leaf spring.
 16. Theassembly of claim 1 wherein the longitudinal axis has a substantiallyvertical orientation.
 17. The assembly of claim 1 wherein thelongitudinal axis has a substantially horizontal orientation.
 18. Adynamic bushing assembly for preventing a tubular member from movingtransverse to a longitudinal axis defined thereby but permitting thetube to be rotated about the longitudinal axis, the assembly comprising:a tube retaining area, the tube retaining are being defined by a baseblock, the base block defining a substantially V-shaped groove having afirst side and a second side and defining an angle therebetween, thesubstantially V-shaped groove constructed and arranged to receivinglyand removably engage a tubular member positioned therein, the tubularmember having an external surface and being disposed about alongitudinal axis, the first side of the substantially V-shaped grooveconstructed and arranged to tangentially contact the external surface ofthe tubular member along at least one line of contact parallel to thelongitudinal axis, the second side of the substantially V-shaped grooveconstructed and arranged to tangentially contact the external surface ofthe tubular member along at least one line of contact parallel to thelongitudinal axis; and an arm member, the arm member being pivotallyengaged to a portion of the base block adjacent to the substantiallyV-shaped groove, the arm member being pivotally moveable from an openposition to a closed position, in the closed position at least a portionof the arm member constructed and arranged to tangentially contact theexternal surface of the tubular member along at least one line ofcontact parallel to the longitudinal axis.
 19. The assembly of claim 18wherein the assembly is oriented so that the tubular member is retainedwithin the substantially V-shaped groove by gravitational pull.
 20. Theassembly of claim 18 wherein the assembly is oriented so that the armmember is retained in the close position by gravitational pull.
 21. Theassembly of claim 20 wherein the arm member comprises a ballast member,the ballast member having a weight.
 22. The assembly of claim 21 whereinthe weight of the ballast member is about {fraction (1/2)} of a pound (8oz., 227 grams) or less.
 23. The assembly of claim 21 wherein the weightof the ballast member is about {fraction (1/4)} of a pound (4 oz., 113grams) to about {fraction (3/8)} of a pound (6 oz. 170 grams).
 24. Theassembly of claim 18 wherein the arm member further comprises a biasingmechanism, the biasing mechanism constructed and arranged to removablyretain the arm member in the closed position.
 25. The assembly of claim24 wherein the biasing mechanism is a compression spring or an aircylinder.
 26. The assembly of claim 18 wherein the first side and thesecond side of the substantially V-shaped groove are at least partiallyconstructed from a material having a hardness of at least 64 as measuredon the Rockwell-C hardness scale.
 27. The assembly of claim 18 whereinthe first side and the second side of the substantially V-shaped grooveat least partially define a carbide insert.
 28. The assembly of claim 18wherein the first side and the second side of the substantially V-shapedgroove are wire burned.
 29. The assembly of claim 18 wherein the firstside and the second side of the substantially V-shaped groove arepolished.
 30. The assembly of claim 18 wherein the first side and thesecond side of the substantially V-shaped groove are at least partiallycoated with a hardening agent.
 31. The assembly of claim 18 wherein thefirst side and the second side of the substantially V-shaped groove areat least partially coated with tin or titanium nitrate.
 32. The assemblyof claim 18 wherein the first side and the second side of thesubstantially V-shaped groove are at least partially coated with alubricant.
 33. The assembly of claim 18 wherein at least one of thefirst side and the second side of the substantially V-shaped groovedefine at least one fluid injection ports for injecting fluid into thetube retention area, the at least one fluid injection port being influid communication through the base block with a fitting.
 34. Theassembly of claim 33 wherein the fluid is a coolant.
 35. The assembly ofclaim 18 wherein the at least a portion of the arm member is acylindrical contact member.
 36. The assembly of claim 35 wherein thecylindrical contact member is moveable relative to the arm and thetubular member.
 37. The assembly of claim 18 wherein the at least aportion of the arm member defines an edge.
 38. The assembly of claim 18wherein the longitudinal axis has a substantially vertical orientation.39. The assembly of claim 18 wherein the longitudinal axis has asubstantially horizontal orientation.
 40. A dynamic bushing assembly forpreventing a tubular member from moving transverse to a longitudinalaxis defined thereby but permitting the tube to be rotated about thelongitudinal axis, the assembly comprising: a tooling block, the toolingblock having a first end and a second end and defining a tube retentionarea that extends through the tooling block from the first end to thesecond end, the tube retention area defining a longitudinal axistherethrough, the tooling block further defining at least one fluidinjection port, the at least one fluid injection port in fluidcommunication with the tube retention area, the at least one fluidinjection port constructed and arranged to inject a fluid into the tuberetention area; a first gland plate, the first gland plate being engagedto the first end of the tooling block and defining a first openingtherethrough, the first opening in fluid communication with the tuberetention area; and a second gland plate, the second gland plate beingengaged to the second end of the tooling block and defining a secondopening therethrough, the second opening in fluid communication with thetube retention area.
 41. The assembly of claim 40 wherein the tuberetention area is constructed and arranged to contain a portion of atubular member therein, when the portion of the tubular member ispositioned within the tube retention and the fluid is injected into thetube retention area the assembly acts as a hydraulic bearing preventingthe tubular member from moving transverse to the longitudinal axis. 42.The assembly of claim 41 wherein the first gland plate and the secondgland plate constructed and arranged to minimize loss of fluid from thefirst end of the tube retention area and the second end of the tuberetention area.
 43. The assembly of claim 42 wherein at least one of thefirst gland plate and second gland plate define a labyrinth, thelabyrinth defining at least one pressure reduction area.
 44. Theassembly of claim 43 wherein a first amount of fluid is injected intothe tube retention area and a second amount of fluid exits the tuberetention area from the first gland plate and the second gland plate,the first amount of fluid is greater than the second amount of fluid.45. The assembly of claim 40 wherein the fluid is selected from at leastone member of the group consisting of: water, oils, water solublecutting solutions, and any combination thereof.
 46. The assembly ofclaim 40 wherein the longitudinal axis has a substantially verticalorientation.
 47. The assembly of claim 40 wherein the longitudinal axishas a substantially horizontal orientation.
 48. A gripper mechanism forpreventing a tubular member from moving transverse to a longitudinalaxis defined thereby but permitting the tube to be moved longitudinallyalong the longitudinal axis, the mechanism comprising: at least twoengagement members, the at least two engagement members being moveablefrom an open position to a closed position, in the closed position thetubular member being selectively moveably engaged by the at least twoengagement members, in the open position the tubular member beingreleased from the at least two engagement members; at least one counterweight positioned opposite to the at least two engagement members; andat least one pivot member, wherein the at least two engagement membersand the at least one counter weight are in a substantially balancedgravitational equilibrium about the pivot member.
 49. The mechanism ofclaim 48 wherein the at least two engagement members are positionedsubstantially parallel to one another.
 50. The mechanism of claim 48wherein the at least two engagement members are positioned angularlyoffset from one another.
 51. The mechanism of claim 48 wherein each ofthe at least two engagement members comprise a jaw structure, the jawstructure having a gripping surface, in the closed position the tubularmember being selectively moveably engaged by the griping surface. 52.The mechanism of claim 51 wherein the gripping surface is softer thanthe jaw structure.
 53. The mechanism of claim 51 wherein the grippingsurface is at least partially constructed of at least one material ofthe group consisting of: cloth, natural fiber, artificial fiber,leather, or any combination thereof.
 54. The mechanism of claim 51wherein the gripping surface is at least partially constructed of afirst material and a second material, wherein the first material has ahardness that is different than that of the second material.
 55. Themechanism of claim 51 wherein the gripping surface is at least partiallyconstructed of at least one member of the group consisting of wool,polyester, nylon, cotton and any combination thereof.
 56. A tubularmember cutting assembly comprising: a gripper mechanism for preventingthe tubular member from moving transverse to a longitudinal axis definedthereby but permitting the tube to be moved longitudinally along thelongitudinal axis, the mechanism having: at least two engagementmembers, the at least two engagement members being moveable from an openposition to a closed position, in the closed position the tubular memberbeing selectively moveably engaged by the at least two engagementmembers, in the open position the tubular member being released from theat least two engagement members, at least one counter weight positionedopposite to the at least two engagement members, and at least one pivotmember, wherein the at least two engagement members and the at least onecounter weight are in a substantially balanced gravitational equilibriumabout the pivot member; and at least one dynamic bushing assembly forpreventing the tubular member from moving transverse to the longitudinalaxis but permitting the tube to be rotated about the longitudinal axisselected from at least one assembly of the group consisting of: theassembly comprising: a tube retention area, the tube retention areabeing defined at least partially defined by a crown member, the crownmember defining an apex, the apex having at least one top guide memberextending therefrom into the tube retention area, the tube retentionarea being further defined by a substantially concave surface of apiston, the piston being moveable toward and away from the apex, thesubstantially concave surface of the piston having at least two bottomguide members extending therefrom into the tube retention area; theassembly comprising: a tube retaining area, the tube retaining are beingdefined by a base block, the base block defining a substantiallyV-shaped groove having a first side and a second side and defining anangle therebetween, the substantially V-shaped groove constructed andarranged to receivingly and removably engage a tubular member positionedtherein, the tubular member having an external surface and beingdisposed about a longitudinal axis, the first side of the substantiallyV-shaped groove constructed and arranged to tangentially contact theexternal surface of the tubular member along at least one line ofcontact parallel to the longitudinal axis, the second side of thesubstantially V-shaped groove constructed and arranged to tangentiallycontact the external surface of the tubular member along at least oneline of contact parallel to the longitudinal axis, and an arm member,the arm member being pivotally engaged to a portion of the base blockadjacent to the substantially V-shaped groove, the arm member beingpivotally moveable from an open position to a closed position, in theclosed position at least a portion of the arm member constructed andarranged to tangentially contact the external surface of the tubularmember along at least one line of contact parallel to the longitudinalaxis; the assembly comprising: a tooling block, the tooling block havinga first end and a second end and defining a tube retention area thatextends through the tooling block from the first end to the second end,the tube retention area defining a longitudinal axis therethrough, thetooling block further defining at least one fluid injection port, the atleast one fluid injection port in fluid communication with the tuberetention area, the at least one fluid injection port constructed andarranged to inject a fluid into the tube retention area; a first glandplate, the first gland plate being engaged to the first end of thetooling block and defining a first opening therethrough, the firstopening in fluid communication with the tube retention area, and asecond gland plate, the second gland plate being engaged to the secondend of the tooling block and defining a second opening therethrough, thesecond opening in fluid communication with the tube retention area; andany combination thereof.